Encyclopedia Astronautica
Nuclear/Ammonia


Nuclear thermal engines use the heat of a nuclear reactor to heat a propellant. Although early Russian designs used ammonia or an ammonia/alcohol mixture as propellant, the ideal working fluid for space applications is the liquid form of the lightest element, hydrogen. Although successfully ground-tested in both Russia, they have never been flown due primarily to environmental and safety concerns.

It is a relatively high-boiling gas with a vapour pressure of 8.7 bar at 20 deg C. Ammonia. is toxic, and will dissolve easily in water. It will form flammable and explosive mixtures with air. Although ammonia itself is toxic, the exhaust gases from the combustion of ammonia and oxygen are not. Ammonia is produced by a Haber-Bosch process, in which the elements, nitrogen and hydrogen, are united at a temperature of 500 to 600 deg C and a. pressure of approximately 200 bar in the presence of a promoted iron catalyst. It is estimated that 4 million tonnes of anhydrous synthetic ammonia were produced in 1959 in the United States, at which time the price of tank-car quantities of refrigeration-grade anhydrous ammonia was $ 80 per tonne.

Oxidizer: Nuclear. Oxidizer: Nuclear. Fuel: Ammonia. Fuel: Ammonia+Alcohol. Propellant Formulation: Nuclear/NH3+Alcohol (C2H5OH). Fuel Density: 0.604 g/cc. Fuel Freezing Point: -78 deg C. Fuel Boiling Point: -33 deg C.

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Associated Engines
  • YaRD OKB-456 Glushko nuclear/ammonia rocket engine. 1373 kN. Development ended 1960. Isp=470s. Used nuclear reactor in cylindrical housing, operating at 3000 deg K. Propellant heated in the reactor and exhausted through four expansion nozzles More...

Associated Stages
  • Superraket Block B Nuclear/Ammonia propellant rocket stage. Loaded/empty mass 700,000/75,000 kg. Thrust 8,330.00 kN. Vacuum specific impulse 550 seconds. Nuclear engine operating at 3500 deg K. Mass estimated; empty mass calculated. More...
  • YaKhR-2 Core Nuclear/Ammonia propellant rocket stage. Loaded/empty mass 180,000/22,000 kg. Thrust 1,660.00 kN. Vacuum specific impulse 470 seconds. Engines in development by Bondayuk and Glushko. Alternate propellants ammonia only or ammonia/alcohol mixture. Four expansion nozzles fed by single reactor. Masses calculated based on given vehicle gross weight and performance. More...
  • YaRD ICBM OKB-456 Nuclear/Ammonia propellant rocket stage. Loaded/empty mass 84,400/8,600 kg. Thrust 1,370.00 kN. Vacuum specific impulse 470 seconds. Nuclear-propelled ICBM with engines in development by Glushko. Four expansion nozzles fed by single reactor. Payload 2,600 kg to 14,000 km. Empty mass, vehicle length calculated. More...

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